Stacking Box single and double

This ist a Stacking Box in single in double version.
The single version is: 9 x 19 x 8 cm
The double version is: 18 x 19 x 8 cm

You can stack
- two single boxes on a double box
- a double box on two single boxes
- a double box on a double box
- a single box on a single box

You can use sign plates to know what is in the boxes.

For the boxes use plywood 4 mm, for the sign plates 3mm.
You also need 4 bolts M3 x 18 mm and 4 nuts M3